Spatially resolved measurements of the resistive transition in epitaxial YBa2Cu3O7-films

doi:10.1016/0921-4534(90)90489-2

Physica C: Superconductivity

Volume 167, Issues 1–2, 15 April 1990, Pages 79-88

https://doi.org/10.1016/0921-4534(90)90489-2 Get rights and content

Abstract

The spatial distribution of the resistive transition for laser deposited c-axis oriented epitaxial YBa₂Cu₃O₇-films on &:#60;100> SrTiO₃ has been imaged by low temperature scanning electron microscopy (LTSEM) with a spatial resolution of about 1 μm. The films which have critical current densities up to 5 × 10⁶ A/cm² at 77 K show temperature variations in the local resistive transition curves up to 200 mK. Possible reasons for the observed inhomogeneous behavior are discussed.

References (14)

R. Gross et al.
Cryogenics
(1989)
R. Gross et al.
Nature
(1988)
M. Hartmann et al.
Z. Phys. B
(1989)
J. Mannhart et al.
Science
(1989)
R. Gross et al.
Appl. Phys. Lett.
(1989)
P. Chaudary et al.
Phys. Rev. Lett.
(1988)
J. Mannhart et al.
Phys. Rev. Lett.
(1988)

There are more references available in the full text version of this article.

Cited by (17)

Observation of nonuniform current transport in epitaxial YBa <inf>2</inf>Cu<inf>3</inf>O<inf>7-x</inf> film near the superconducting transition temperature
2004, Physica C: Superconductivity and its Applications
We have studied the local transport properties in an epitaxial YBa₂Cu₃O_7−x (YBCO) film on LaAlO₃ (LAO) using variable temperature scanning laser microscope (VTSLM) near the superconducting transition. A map of the superconducting transition temperature (T_c^*) is generated from a series of VTSLM images. The map of T_c^* indicates there are inhomogeneities in the film large enough to create nonuniform current flow near the superconducting transition. The evaluated T_c^* varies between 90.3 and 91.0 K in the film. Even though such change in T_c^* is not large enough to be detected by other localized compositional and structural characterization techniques, this along with an area of lower T_c^* and/or higher resistance affects current flow near the superconducting transition temperature as shown in VTSLM images. This inhomogeneity may be caused by slight variations of the stoichiometry and/or oxidation of the YBCO film.
Equivalence of LTSLM and LTSEM analyses: Study of a YBa<inf>2</inf>Cu<inf>3</inf>O<inf>7</inf> multi-layer device
1997, Physica C: Superconductivity and its Applications
Low-temperature scanning electron microscopy (LTSEM) and low-temperature scanning laser microscopy (LTSLM) are both methods for analyzing local electrical properties of superconducting devices. With both techniques we have investigated a YBa₂Cu₃O₇ (YBCO) multi-layer device on a SrTiO₃ (100) substrate namely a micro-bridge containing a set of crossovers. We find that critical current density and critical temperature of this device are reduced at the edges of the crossovers. Complete equivalence of the results obtained for LTSEM and LTSLM has been found, in particular concerning the spatial distribution, the temperature dependence, and the strength of the signal.
Eddy current technique for testing large-area, high T<inf>c</inf> superconducting films with high spatial resolution
1995, Cryogenics
An eddy current technique has been developed which allows non-destructive quality testing of high temperature superconducting thin films with a spatial resolution of ≈50 μm. This technique allows inexpensive and fast diagnosis of large-area superconducting films on substrates with a diameter up to 6 in. The eddy current probe is scanned over the surface of the superconducting film without the need for extra electrical or mechanical attachments. Reports are given on experiments with both well defined test geometries and large-area epitaxial YBa₂Cu₃O_{7 − δ} films prepared on 4 in silicon wafers.
Dry-etching processes for high-temperature superconductors
1992, Physica C: Superconductivity and its applications
Patterning of thin films and multilevel structures of high-temperature superconductors is a key technology for microelectronic applications. We performed a comparative study of Ion Beam Etching (IBE) and Reactive Ion Etching (RIE) processes for YBa₂Cu₃O_7−δ thin films. The RIE process with a pure chlorine plasma yielded small etching rates, caused by chemical modifications of the sample surface which result in a passivation layer reducing the chemical etching rate. Using IBE, microstructures down to the 1 μm regime could be fabricated without reducing the critical temperature T_c and the critical current density J_c of the material. Etching rates up to 40 nm/min could be achieved without deteriorating the properties of the superconducting film by cooling the sample effectively during the etching process. The influence of the etching process on J_c was investigated by imaging the spatial distribution of the critical current along the patterned microstructures using Low-Temperature Scanning Electron Microscopy (LTSEM).
Low-temperature scanning electron microscopy studies of superconducting thin films and Josephson junctions
1991, Physica B: Physics of Condensed Matter
Scanning techniques represent powerful methods for the characterization of condensed matter. Extending Scanning Electron Microscopy (SEM) to the range of low temperatures an interesting tool for studying low-temperature properties of solids with high-spatial and temporal resolution is obtained. By Low-Temperature Scanning Electron Microscopy (LTSEM) important new information on low-temperature phenomena in superconductors, semiconductors, and insulators is obtained by two-dimensional imaging. Here, we summarize the basic principles of LTSEM and show its application to the study of superconducting films and Josephson junctions.
Spatially resolved analyses of epitaxial and electrical properties of YBa2Cu3O7 devices
1996, Applied Physics Letters

View all citing articles on Scopus

View full text

Spatially resolved measurements of the resistive transition in epitaxial YBa2Cu3O7-films

Abstract

Cryogenics

Nature

Z. Phys. B

Science

Appl. Phys. Lett.

Phys. Rev. Lett.

Phys. Rev. Lett.

Spatially resolved measurements of the resistive transition in epitaxial YBa₂Cu₃O₇-films